The invention provides a confocal microscope or endoscope, having a source of coherent light for illuminating a sample, and an imaging optical fibre bundle (82) for receiving return light, whereby the fibre bundle (82) provides a return channel for fluorescent return light (78). The optical fibre bundle (82) preferably preserves, between entry and exit ends of the bundle, the relative spatial coordinates of the cores of individual fibres constituting the bundle.